We performed a prospective study of hospice in-patients requiring a syringe driver (SD), to determine the site duration and tolerability of metal butterfly needles compared to Teflon cannulae. Using patients as their own control, prescribed medications were divided equally between two SDs (Graseby MS16a), for delivery over 24 h. A butterfly infusion (Flosafer, 25 gauge) was connected to one SD and a Teflon cannula (Abbocath-T, 24 gauge), to the second. These were inserted subcutaneously (s.c.) on opposite sides of the body at comparable sites; oedematous, broken or painful sites were excluded. SD sites were examined at 4-hourly intervals. The study was terminated when both devices had required resiting. Needle and cannula times were compared using the Wilcoxon signed rank test. Thirty patients entered the study, 13 males and 17 females, mean age (standard deviation): 70 (11) years. Thirteen patients completed the study. Nine patients died and eight patients discontinued the study before both needle and cannula had been resited. All 30 patients are included in the analysis. The time from insertion to resiting of the cannula was significantly longer than the needle: P < 0.0002, median (range) 93.5 (22.8-263.5) h versus 42.8 (7.5-162.3) h, respectively. The cost of the needle versus cannula is 1.93 Pounds versus 2.51 Pounds, respectively. Teflon cannulae have a median life span twice that of metal butterfly needles and are a cost-effective alternative for administration of medications by s.c. infusion in terminally ill patients.